new version of fake sensors

[jho59]

Hi,

of course I know, that 20 sensors for 5 Euro can't be original. What I got from a chinese platform:

1. Front side for TO92 case is lasered, but some lines are dots with gaps.
2. 64bit IDs are of correct pattern.
3. Can switch between 9, 10, 11, 12bit resolution. Values increments of 0.5°C, 0.25°C etc.
4. Conversion time is 2 ms - yes TWO milliseconds. The sensors don't recognize value of waitForConversion.

Bye, Jürgen

[cpetrich]

Thank you for the pointer.
Just had a look, seems like the number of distributors (manufacturers)? is proliferating.
Planning on following up on this.
Can you share a ROM and the marking on the case?

[jho59]

Hi,

1. The marking is:
   DALLAS
   18B20
   2402C4
   +817AB
   On backside a dent, but no character P.

2. Don't know, what you mean with "share a ROM". I let discover_fake_DS18B20.ino run:

28-3E-43-87-00-00-00-18: ROM ok.
Scratchpad Register: 90/01/7F/80/7F/FF/10/10/1D
Info only: Scratchpad bytes 2,3,4 (7F/80/7F): not Maxim default values 4B/46/7F.
Scratchpad byte 5 (0xFF): ok.
Scratchpad byte 6 (0x10): ok.
Scratchpad byte 7 (0x10): ok.
0x4E modifies alarm registers: ok.
0x4E accepts 10 bit resolution: ok.
0x4E preserves reserved bytes: ok.
0x4E accepts 12 bit resolution: ok.
0x4E preserves reserved bytes: ok.
Checking byte 6 upon temperature change: not necessary. Skipped.
--> Sensor responded like a genuie Maxim.
Not tested: EEPROM, Parasite Power, and undocumented commands.

[uzi18]

Please try to check parasite mode - fakes got problem with report power status

[jho59]

1. Sensors don't send 0 as long as conversion is ongoing and 1 when finished. So they are useless in my opinion. So why should I spend more time to try out parasite-powered mode?
2. Datasheet shows a MOSFET, but make no suggestion about type. At the moment I don't have anything for Vdd = 3,3V.

[cpetrich]

I think I managed to purchase these chips from a different supplier (mine were not marked DALLAS). I added them as a new Family H to the list. I still have to update the sketches and some parts of the summary to account for the new Families.

Again, I much appreciate your pointer.

[cpetrich]

rebranded as Family A3